Numerous devices for coupling hoses are known in the art. In many operations, varying lengths of hose are required, and it is necessary to adjust the hose length in order to accomplish the task at hand. Hose segments of the same or differing lengths may be fitted together in order to create one hose having the desired length for any particular job or location.
It is also a common practice to couple hoses of decreasing diameter in order to increase the flow rate of the liquids or gases passing through the hoses, by creating a venturi effect. Often these flows will be under high pressure and will have entrained particulate matter therein.
Coupling devices must maintain an effective seal between the hoses to be coupled, in order to prevent leaking. It is a common practice to have two interconnecting sections, each mounted on one end of separate hoses. The two sections are then connected together, and a seal is created between the sections. Conventionally, a grommet or washer is employed to effect the seal.
Hoses employed in high pressure operations, such as those encountered in sand blasting, present a unique set of special concerns which must be considered. Because of the increased dynamic forces upon the hoses and the attendant couplings in such operations, seal integrity is of utmost importance. A high velocity stream of particulate matter can cause severe damage and injury if not contained.
It has been found, that when couplings are provided with rubber or polymeric grommets and washers, the seal is maintained only as long as these components remain essentially intact. High velocity, particulate matter streams tend to cause degradation of washers after short operating time. The washers known to applicant have projecting edges, which when subjected to a particulate matter flow, are easily damaged.
Even slight degradation of a washer may lead to seal failure, especially given the dynamics of the forces in a high pressure operation. Seal failure will permit the contained stream to escape, often at even a higher flow rate than had occurred within the hose, due to an induced, quasi-venturi effect. Such an escape may cause, and has been known to cause, severe injury and damage to proximate persons and objects.
Therefore, a need exists for a hose coupling, and specifically for a coupling for hoses used in high pressure operations, which maintains seal integrity despite wear tendencies caused by the flowing stream.